I/O modules • 241
RS232C interface 750-650
Modular I/O System
ETHERNET TCP/IP
Attention
The data transmission takes place at 9,600 baud (default value). 1 start bit, 8
data bits and 1 stop bit will be transmitted. No parity is available. The user
controls data via the RTS and CTS signals. These signals are generated in the
module depending on the loading status of the buffers. These controls can be
deactivated by means of an external jumper. RTS and CTS are to be connec-
ted.
Attention
For testing purposes the Windows terminal emulation
can be used. A
cable with a 9- pole sub-D socket is required. Pin 5 is connected to input
"common". Pin 2 is connected to TxD and Pin 3 to RxD. RTS and CTS of the
module are connected. A hardwarehandshake between the terminal emulation
and the PLC is not possible.
Organization of the in- and output data:
The module is a combined analog input and output module with 2 x 16 bit in-
put and output data. The transfer of the data to be transmitted and the received
data is made via 3 output and 3 input bytes. One control byte and one status
byte are used to control the floating data.
Requests are indicated by a change of a bit. An assigned bit indicates executi-
on by adopting the value of the request bit.
Up to 3 characters which have been received via interface can be stored in the
input bytes 0 to 2. The output bytes will contain the characters to be sent.
The control byte consists of the following bits:
Bit 7
Bit 6
Bit 5
Bit 4
Bit 3
Bit 2
Bit 1
Bit 0
0
OL 2
OL1
OL0
0
IR
RA
TR
Constant
value
should
always
be 0.
Frames available in output area
OL2 is always 0,
i.e. OL2, OL1, OL0 = 0,1,1
3 characters should be sent and put
into the output.
Constant
value
should
always
be 0.
Initialization
request
Receive
acknow-
ledge
Transmit
request
The status byte has the following bits:
Bit 7
Bit 6
Bit 5
Bit 4
Bit 3
Bit 2
Bit 1
Bit 0
0
IL2
IL1
Il0
BUF_F
IA
RR
TA
Constant
value
should
always
be 0.
Frames available in input area
IL2 is always 0.
i.e. IL2, IL1, IL0 = 0,1,0
2 characters were received and
reside in input 0 and input 1.
Input
buffer is
full.
Initialization
acknowledge
Receive
request
Transmit
acknow-
ledge
The PLC/PC is able to control transmission and reception of data by means of
the control byte and the status byte.
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